The La Brea Tar Pits is an active paleontological research site in urban Los Angeles. Hancock Park was formed around a group of tar pits where natural asphalt (also called asphaltum, bitumen, or pitch; brea in Spanish) has seeped up from the ground for tens of thousands of years. Over many centuries, the bones of trapped animals have been preserved. The George C. Page Museum is dedicated to researching the tar pits and displaying specimens from the animals that died there. La Brea Tar Pits is a registered National Natural Landmark.

Only one human has been found, a partial skeleton of the La Brea Woman dated to 10,220–10,250 years BP, who was 17 to 25 years old at death and found associated with remains of a domestic dog, so was interpreted to have been ceremonially interred. In 2016, however, the dog was determined to be much younger in date.

Also, some even older fossils showed possible tool marks, indicating humans were active in the area at the time. Bones of saber-toothed cats from La Brea showing signs of "artificial" cut marks at oblique angles to the long axis of each bone were radiocarbon dated to 15,200 ± 800 B.P. (uncalibrated).

If these cuts are in fact tool marks resultant from butchering activities, then this material would provide the earliest solid evidence for human association with the Los Angeles Basin. Yet it is also possible that there was some residual contamination of the material due to saturation by asphaltum, influencing the radiocarbon dates.